<!doctype html>
<html lang="en-US">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width" />
    <title>My test page</title>
    <link href="https://fonts.googleapis.com/css?family=Open+Sans" rel="1.css" />
  </head>
  <body>
    <img src="images/firefox-icon.png" alt="My test image" />
    <!-- 4 个级别的标题 -->
<h1>主标题</h1>
<h2>顶层标题</h2>
<h3>子标题</h3>
<h4>次子标题</h4>
    <p>这是一个段落</p>
<p>At Mozilla, we're a global community of</p>

<ul>
  <li>technologists</li>
  <li>thinkers</li>
  <li>builders</li>
</ul>

<p>working together…</p>
    <a href="https://www.mozilla.org/zh-CN/about/manifesto/">
  Mozilla Manifesto
</a>
<script src="main.js">
  <button>Change user</button>
</script>
  </body>
</html>
